Information contained in this manual is intended for use by
qualified service technicians only. All specifications are sub-
ject to change.
WARNINGImproper installation, adjustment, alteration, serviceor maintenance can cause property damage, person-al injury or loss of life. Installation and service mustbe performed by a qualified installer or serviceagency.
WARNINGWarranty will be voided if covered equipment is re-moved from original installation site. Warranty willnot cover damage or defect resulting from:Flood, wind, lightning, or installation and operationin a corrosive atmosphere (chlorine, fluorine, salt,recycled waste water, urine, fertilizers, or other dam-aging chemicals).
DANGERShock Hazard
Remove all power at disconnectbefore removing access panel.Single phase XC16 units use single-pole contactors. Potentialexists for electrical shock resultingin injury or death.Line voltage exist at all components(even when unit is not in operation).
IMPORTANTOperating pressures of this R−410A unit are higherthan pressures in R−22 units. Always use serviceequipment rated for R410A.
NOTE − Extremes of operating range are plus 10% and minus 5% of line voltage.1 Refrigerant charge sufficient for 15 ft. length of refrigerant lines.2 Refer to National or Canadian Electrical Code manual to determine wire, fuse and disconnect size requirements.3 HACR type breaker or fuse.4 Hard start kit is required in applications where the supply voltage is less than 230V.
Page 3
I − APPLICATION
XC16 condensing units are available in 2, 3, 4 and 5 ton capac-
ities. All major components (indoor blower and coil) must be
matched according to Lennox recommendations for the com-
pressor to be covered under warranty. Refer to the Engineer-
ing Handbook for approved system matchups.
II − UNIT COMPONENTSUnit components are illustrated in figure 1.
XC16 PARTS ARRANGEMENT
FIGURE 1
DUAL CAPACITOR
CONTACTOR
OUTDOOR FAN
COMPRESSOR
HIGHPRESSURE
SWITCH
FILTER DRIER
LOWPRESSURE
SWITCH
CAUTIONTo prevent personal injury, or damage to panels, unitor structure, be sure to observe the following:
While installing or servicing this unit, carefully stowall removed panels out of the way, so that the panelswill not cause injury to personnel, nor cause damageto objects or structures nearby, nor will the panels besubjected to damage (e.g., being bent or scratched).
While handling or stowing the panels, consider anyweather conditions, especially windy conditions, thatmay cause panels to be blown around and battered.
Remove the louvered panels as follows:
1 − Remove 2 screws, allowing the panel to swing openslightly (see figure 2).
DetailA
Detail C
DetailB
FIGURE 2
Removing/Installing Louvered Panels
MAINTAIN MINIMUM PANEL ANGLE (AS CLOSE TO PARALLEL WITH THE UNITAS POSSIBLE) WHILE INSTALLING PANEL.
PREFERRED ANGLEFOR INSTALLATION
Detail D
ROTATE IN THIS DIRECTION;THEN DOWN TO REMOVE PANEL
SCREWHOLES
ANGLE MAY BE TOOEXTREME
HOLD DOOR FIRMLY TO THE HINGED SIDE TO MAINTAIN
FULLY−ENGAGED TABS
LIP
IMPORTANT! Do not allow panels to hang on unit by top tab. Tabis for alignment and not designed to support weight of panel.
Panel shown slightly rotated to allow top tab to exit (or enter) topslot for removing (or installing) panel.
2 − Hold the panel firmly throughout this procedure. Ro-tate bottom corner of panel away from hinge corner postuntil lower 3 tabs clear the slots (see figure 2, Detail B).
3 − Move panel down until lip of upper tab clears the top slotin corner post (see figure 2, Detail A).
Page 4
Position and Install Panel�Position the panel almost par-allel with the unit (figure 2, Detail D) with the �screw side" asclose to the unit as possible. Then, in a continuous motion:
Slightly rotate and guide the lip of top tab inward (figure 2,Details A and C); then upward into the top slot of thehinge corner post.
Rotate panel to vertical to fully engage all tabs.
Holding the panel’s hinged side firmly in place, close theright−hand side of the panel, aligning the screw holes.
When panel is correctly positioned and aligned, insert thescrews and tighten.
A − Control Box (Figure 3)
XC16 units are not equipped with a 24V transformer. All 24
VAC controls are powered by the indoor unit. Refer to wir-
ing diagram.
Electrical openings are provided under the control box cov-
er. Field thermostat wiring is made to color-coded pigtail
connections.
ELECTROSTATIC DISCHARGE (ESD)
Precautions and Procedures
CAUTION
Electrostatic discharge can affect electronic com-ponents. Take precautions during unit installationand service to protect the unit’s electronic controls.Precautions will help to avoid control exposure toelectrostatic discharge by putting the unit, the con-trol and the technician at the same electrostatic po-tential. Neutralize electrostatic charge by touchinghand and all tools on an unpainted unit surface be-fore performing any service procedure.
FIGURE 3
DUAL CAPACITOR(C12)
COMPRESSORCONTACTOR
(K1)
CONTROL BOX
GROUNDINGLUG
TIMED OFFCONTROL.(OPTION)
1 − Compressor Contactor (K1)The compressor is energized by a single−pole contactor lo-
cated in the control box. See figure 3. K1 is energized by the
indoor thermostat terminal Y1 (24V) when thermostat de-
mand is present.
2 − Dual Capacitor (C12)The compressor and fan in XC16 series units use perma-
nent split capacitor motors. The capacitor is located in-
side the unit control box (see figure 3). A single �dual" ca-
pacitor (C12) is used for both the fan motor and the com-
pressor (see unit wiring diagram). The fan side and the
compressor side of the capacitor have different MFD rat-
ings. See side of capacitor for ratings.
3 − Start Kit (option)
The start kit consists of a potential relay K31 and start capac-
itor C7. The potential relay controls the operation of the
starting circuit. The relay is normally closed when contactor
K1 is de−energized. When K1 is energized, the compressor
immediately begins start up. K31 remains closed during
compressor start up and and start capacitor C7 remains in
the circuit. When compressor reaches approximately 75%
of its speed, K31 is energized. When K31 energizes, the
contacts open and start capacitor C7 is taken out of the cir-
cuit.
4 − Timed Off Control TOC (option)The time delay is electrically connected between thermostat
terminal Y and the compressor contactor. Between cycles,
the compressor contactor is delayed for 5 minutes ± 2 min-
utes but may last as long as 8 minutes. At the end of the
delay, the compressor is allowed to energize. When thermo-
stat demand is satisfied, the time delay opens the circuit to
the compressor contactor coil and the compressor is de−en-
ergized.
Page 5
B − Two−Stage Scroll Compressor (B1)
CAUTIONIn order to avoid injury, take precaution whenlifting heavy objects.
FIGURE 1
TWO−STAGE MODULATED SCROLL
solenoid actuator coil
slider ring
The scroll compressor design is simple, efficient and re-
quires few moving parts. A cutaway diagram of the scroll
compressor is shown in figure 1.The scrolls are located in
the top of the compressor can and the motor is located just
below. The oil level is immediately below the motor.
The scroll is a simple compression concept centered around
the unique spiral shape of the scroll and its inherent proper-
ties. Figure 2 shows the basic scroll form. Two identical
scrolls are mated together forming concentric spiral shapes
(figure 3 ). One scroll remains stationary, while the other is
allowed to �orbit" (figure 4). Note that the orbiting scroll does
not rotate or turn but merely �orbits" the stationary scroll.
FIGURE 2
SCROLL FORM
FIGURE 3
STATIONARYSCROLL
ORBITING SCROLL
DISCHARGE
SUCTION
CROSS−SECTION OF SCROLLS
TIPS SEALED BYDISCHARGE PRESSURE
DISCHARGEPRESSURE
The counterclockwise orbiting scroll draws gas into the outer
crescent shaped gas pocket created by the two scrolls (figure
4 − 1). The centrifugal action of the orbiting scroll seals off the
flanks of the scrolls (figure 4 − 2). As the orbiting motion con-
tinues, the gas is forced toward the center of the scroll and the
gas pocket becomes compressed (figure 4 −3). When the
compressed gas reaches the center, it is discharged vertical-
ly into a chamber and discharge port in the top of the com-
pressor (figure1). The discharge pressure forcing down on
the top scroll helps seal off the upper and lower edges (tips) of
the scrolls (figure 3 ). During a single orbit, several pockets of
gas are compressed simultaneously providing smooth con-
tinuous compression.
The scroll compressor is tolerant to the effects of liquid re-
turn. If liquid enters the scrolls, the orbiting scroll is allowed
to separate from the stationary scroll. The liquid is worked
toward the center of the scroll and is discharged. If the com-
pressor is replaced, conventional Lennox cleanup practices
must be used.
Due to its efficiency, the scroll compressor is capable of
drawing a much deeper vacuum than reciprocating com-
pressors. Deep vacuum operation can cause internal fusite
arcing resulting in damaged internal parts and will result in
compressor failure. This type of damage can be detected
and will result in denial of warranty claims. The scroll com-
pressor can be used to pump down refrigerant as long as
the pressure is not reduced below 7 psig.
The scroll compressors in all XC16 model units are de-
signed for use with R410A refrigerant and operation at high
pressures. Compressors are shipped from the factory with
3MA (32MMMA) P.O.E. oil. See electrical section in this
manual for compressor specifications.
NOTE − During operation, the head of a scroll compressor
may be hot since it is in constant contact with discharge
gas.
Page 6
TWO−STAGE OPERATION
NOTE − During operation, the head of a scroll compressormay be hot since it is in constant contact with dischargegas.
The two−stage scroll compressor operates like any standard
scroll compressor with the exception the two−stage com-
pressor modulates between first stage (low capacity
approximately 67%) and second stage (high capacity).
Modulation occurs when gas is bypassed through bypass
ports (figure 5 bypass ports open) in the first suction pocket.
This bypassing of gas allows the compressor to operate on
first stage (low capacity) if thermostat demand allows. In-
door thermostat setting will determine first or second stage
operation. The compressor will operate on first−stage until
demand is satisfied or the indoor temperature reaches the
thermostat set point calling for second−stage.
Second−stage (high capacity) is achieved by blocking the
bypass ports (figure 5 bypass ports closed) with a slider ring.
The slider ring begins in the open position and is controlled
by a 24VDC internal solenoid. On a Y2 call the internal sole-
noid closes the slider ring, blocking the bypass ports and
bringing the compressor to high capacity. Two−stage modu-
lation can occur during a single thermostat demand as the
motor runs continuously while the compressor modulates
from first−stage to second− stage.
FIGURE 4
SCROLL
HOW A SCROLL WORKS
SUCTION SUCTION
SUCTION
MOVEMENT OF ORBIT
STATIONARY SCROLL
ORBITING
CRESCENTSHAPED GAS
POCKET
HIGHPRESSURE
GAS
DISCHARGEPOCKET
FLANKSSEALED BY
CENTRIFUGALFORCE
1 2
3 4
SUCTION
INTERMEDIATEPRESSURE
GAS
SUCTIONPOCKET
FIGURE 5
Bypass PortsClosed
High Capacity
Bypass PortsOpen
67% Capacity
TWO STAGE MODULATION
Page 7
INTERNAL SOLENOID (L34)
The internal unloader solenoid controls the two−stage op-
eration of the compressor by shifting a slide ring mechanism
to open two by−pass ports in the first compression pocket of
the scrolls in the compressor. The internal solenoid is acti-
vated by a 24 volt direct current solenoid coil. The coil
power requires 20VAC. The internal wires from the solenoid
in the compressor are routed to a 2 pin fusite connection on
the side of the compressor shell. The external electrical con-
nection is made to the compressor with a molded plug as-
sembly. This plug contains a full wave rectifier that converts
24 volt AC into 24 volt DC power to power the unloader sole-
noid. Refer to unit diagram for internal circuitry view of plug).
If it is suspect the unloader is not operating properly, check
the following
IMPORTANTThis performance check is ONLY valid on systemsthat have clean indoor and outdoor coils, proper air-flow over coils, and correct system refrigerantcharge. All components in the system must be func-tioning proper to correctly perform compressor mod-ulation operational check. (Accurate measurementsare critical to this test as indoor system loading andoutdoor ambient can affect variations between lowand high capacity readings).
STEP 1 Confirm low to high capacity compressor op-
eration
Tools required
Refrigeration gauge set
Digital volt/amp meter
Electronic temperature thermometer
On-off toggle switch
Procedure
1 − Turn main power "OFF" to outdoor unit.
2 − Adjust room thermostat set point above (heating opera-
tion on heat pump) or below (cooling operation) the
room temperature 5ºF.
3 − Remove control access panel. Install refrigeration
gauges on unit. Attach the amp meter to the common
(black wire) wire of the compressor harness. Attach
thermometer to discharge line as close as possible to
the compressor.
4 − Turn toggle switch "OFF" and install switch in series with
Y2 wire from room thermostat.
5 − Cycle main power "ON."
6 − Allow pressures and temperatures to stabilize before
taking any measured reading (may take up to 10 min-
utes).
NOTE − Block outdoor coil to maintain a minimum of 375 psig
during testing).
7 − Record all of the readings for the Y1 demand on table 1.
8 − Close switch to energize Y2 demand.
9 − Allow pressures and temperatures to stabilize before
taking any measured reading (this may take up to 10
minutes).
10 − Record all of the readings of Y2 demand on table 1.
NOTE − On new installations or installations that haveshut down for an extended period of time, if the compres-sor does not cycle from low stage to high stage on thefirst attempt, it may be necessary to recycle the compres-sor back down to low stage and back up to high stage afew times in order to get the bypass seals to properly seat
Compare Y1 readings with Y2 readings in table 1. Somereadings should be higher, lower or the same. If the read-ings follow what table 1 specifies, the compressor is oper-ating and shifting to high capacity as designed. If thereadings do not follow what table 1 specifies, continue tostep 2 to determine if problem is with external solenoidplug power.
Page 8
TABLE 1
Unit ReadingsCooling Operation
Unit ReadingsY1 − 1st-Stage Expected Results Y2 − 2nd-Stage
Compressor
Voltage Same
Amperage Higher
Condenser Fan motor
Amperage Same or Higher
Temperature
Ambient Same
Outdoor Coil Discharge Air Higher
Compressor Discharge Line Higher
Indoor Return Air Same
Indoor Coil Discharge Air Lower
Pressures
Suction (Vapor) Lower
Liquid Higher
STEP 2 Confirm DC voltage output on compressor
solenoid plug
11 − Shut power off to outdoor unit.
12 − Supply 24 volts AC control voltage to the wire ends of
the full wave rectifier plug. Listen for a �click" as the sole-
noid is energized. See figure 6.
compressor
solenoid fusiteterminals
compressorfusite
terminals meter
rectifier plug leads apply 24vac
FIGURE 6
13 − Unplug the full wave rectifier plug from the fusite con-
nection on the compressor.
14 − Turn the low voltage power back onto the unit. Supply
24VAC to the wires of the full wave rectifier plug. Set volt
meter to DC volts and measure the DC voltage at the fe-
male connector end of the full wave rectifier plug. The
DC voltage reading should be 1.5 to 3 volts lower than
the input voltage to the plug wire leads. (EX: Input volt-
age is 24VAC output voltage is 22VDC). See figure 7.
meter
rectifier plug leads
compressorfusite
terminals
solenoidfusite
terminals
compressor
apply 24vac
FIGURE 7
If the above checks verify that the solenoid plug is provid-
ing power to cycle into high capacity operation, continue
to step 3 to determine if problem is with solenoid coil in
compressor
STEP 3 Confirm internal unloader solenoid has prop-
er resistance
15 − Shut all power off to unit (main and low voltage)
16 − Unplug the molded plug from the compressor solenoid
2−pin fusite.
17 − Using a volt meter set on the 200 ohm scale
meter
rectifier plug leads
compressorfusite
terminals
solenoidfusite
terminals
compressor
FIGURE 8
Replace the Compressor under these conditions:
Bad Solenoid
a. Measure the resistance at the 2−pin fusite. See figure 8.
The resistance should be 32 to 60 ohms depending on
compressor temperature. If no resistance replace com-
pressor.
b. Measure the resistance from each fusite pin to ground.
There should not be continuity to ground. If solenoid coil
is grounded, replace compressor.
Good Solenoid
a. Seals not shifting, replace compressor
b. Slider ring not shifting, replace compressor.
Page 9
C − DrierA filter drier designed for all XC16 model units is factory
installed in the liquid line. The filter drier is designed to re-
move moisture and foreign matter, which can lead to com-
pressor failure.
Moisture and / or Acid Check
Because POE oils absorb moisture, the dryness of the
system must be verified any time the refrigerant system
is exposed to open air. A compressor oil sample must be
taken to determine if excessive moisture has been
introduced to the oil. Table 2 lists kits available from Lennox
to check POE oils.
If oil sample taken from a system that has been exposed to
open air does not test in the dry color range, the filter drier
MUST be replaced.
IMPORTANTReplacement filter drier MUST be approved forR−410A refrigerant and POE application.
Foreign Matter Check
It is recommended that a liquid line filter drier be replaced
when the pressure drop across the filter drier is greater than
4 psig.
TABLE 2
KIT CONTENTS TUBE SHELF LIFE
10N46 − Refrigerant Analysis Checkmate−RT700
10N45 − Acid Test Tubes Checkmate−RT750A (three pack)2 − 3 years @ room temperature. 3+years refrigerated
10N44 − Moisture Test TubesCheckmate − RT751 Tubes (threepack)
74N40 − Easy Oil Test TubesCheckmate − RT752C Tubes (threepack)
2 − 3 years @ room temperature. 3+years refrigerated
74N39 − Acid Test Kit Sporlan One Shot − TA−1
FIGURE 9
1− Shut off power to unit.
2− Remove high pressure switch from fitting next to filter drier.(A schrader core is located under the high pressure switch).
3− Install high pressure gauge hose onto high pressure switch fitting.
4− Turn power on to unit and turn room thermostat to call for cooling.
5− Record pressure reading on gauge.
6− Remove hose from high pressure fitting and install on liquid line valve.
7− Read liquid line valve pressure.
8− High pressure fitting pressure − liquid line valve pressure = filter drierpressure drop.
9− If pressure drop is greater than 4 psig replace filter drier. See figure 10.
10− Re−install high pressure switch.
MEASURING FILTER DRIER PRESSURE DROP
FIGURE 10
REPLACING FILTER DRIER
1− Recover all refrigerant from unit.
2− Remove original filter drier.
3− Install new filter drier in existing location or alternate location asshown. Proper brazing procedures should be followed.
4− Evacuate system. See section IV − part B − .
5− Recharge system. See section IV − part C − .
Page 10
D − Condenser Fan Motor (B4)
All units use single−phase PSC fan motors which require a run
capacitor. In all units, the condenser fan is controlled by
the compressor contactor.
ELECTRICAL DATA tables in this manual show specifi-
cations for condenser fans used in XC16’s.
Access to the condenser fan motor on all units is gained
by removing the four screws securing the fan assembly.
See figure 4. The grill fan assembly can be removed from
the cabinet as one piece. See figure 5. The condenser fan
motor is removed from the fan guard by removing the four
nuts found on top of the grill. See figure 5 if condenser fan
motor replacement is necessary.
Make sure all power is disconnected beforebeginning electrical service procedures.
DANGER
FIGURE 4
Removescrews
Removescrews
ALIGN FAN HUB FLUSH WITH END OF SHAFT
FIGURE 5
E − Low Pressure Switch (S87)All XC16 units are equipped with an auto-reset, single-pole/
single-throw low pressure switch is located in the vapor line.
This switch shuts off the compressor by de−energizing K1
when vapor line pressure drops below the factory setting.
The switch is closed during normal operating pressure con-
ditions and is permanently adjusted to trip (open) at 40 + 5
psi. The switch automatically resets when vapor line pres-
sure rises above 90 + 5 psi.
F − High Pressure Switch (S4)
XC16 units are equipped with a high pressure switch that is
located in the liquid line of the compressor. The switch
(SPST, manual reset, normally closed) removes power from
the compressor contactor control circuit when discharge
pressure rises above factory setting at 590 + 10 psi.
G − Crankcase Heater (HR1) &
Thermostat (S40) −048 and −060 units only
Compressor in the XC16−048 and −060 units are equipped
with a 70 watt, belly band type crankcase heater. HR1 pre-
vents liquid from accumulating in the compressor. HR1 is
controlled by a thermostat located on the liquid line. When liq-
uid line temperature drops below 50° F the thermostat closes
energizing HR1. The thermostat will open, de−energizing
HR1 once liquid line temperature reaches 70° F .
Page 11
III − REFRIGERANT SYSTEM
A − Plumbing
Field refrigerant piping consists of liquid and suction lines
from the condensing unit (sweat connections) to the indoor
evaporator coil (sweat connections). Use Lennox L15
(sweat) series line sets as shown in table 1.
TABLE 1
UnitLiquidLine
SuctionLine
L15 Line Sets
−024,3/8 in.
(10 mm)3/4 in.
(19 mm)
L15−4115 ft. − 50 ft.
(4.6 m − 15 m)
−036,−048
3/8 in.(10 mm)
7/8 in.(22 mm)
L15−6515 ft. − 50 ft.
(4.6 m − 15 m)
−0603/8 in.
(10 mm)1−1/8 in.(29 mm)
FieldFabricated
The liquid line and vapor line service valves (figures 6 and 7)
and gauge ports are accessible from the outside of the unit.
Use the service ports for leak testing, evacuating, charging
and checking charge.
Each valve is equipped with a service port which has a facto-
ry−installed Schrader valve. A service port cap protects the
Schrader valve from contamination and serves as the pri-
mary leak seal. Service valves are not rebuildable. If a valve
has failed, you must replace it.
To Access Schrader Port:
1 − Remove service port cap with an adjustable wrench.
2 − Connect gauge to the service port.
3 − When testing is complete, replace service port cap. Tight-en finger tight, then an additional 1/6 turn.
To Open Service Valve:
1 − Remove the stem cap with an adjustable wrench.
2 − Using the adjustable wrench to keep the valve station-ary, use a service wrench with a hex−head extension toback the stem out counterclockwise as far as it will go.
NOTE − Use a 3/16" hex head extension for 3/8" linesizes or a 5/16" extension for large line sizes.
3 − Replace the stem cap. Tighten finger tight, then tightenan additional 1/6 turn.
To Close Service Valve: 1 − Remove the stem cap with an adjustable wrench.
2 − Using the adjustable wrench to keep the valve station-ary, use a service wrench with a hex−head extension toturn the stem clockwise to seat the valve. Tighten thestem firmly.
NOTE − Use a 3/16" hex head extension for 3/8" linesizes or a 5/16" extension for large line sizes.
3 − Replace the stem cap. Tighten finger tight, then tighten anadditional 1/6 turn.
NOTE − Stem cap must be replaced to help preventvalve leakage.
Service Valve(Valve Closed)
Schrader valve opento line set when valve is
closed (front seated)
serviceport
serviceport cap
stem cap
insert hexwrench here
(valve front seated)
to outdoor coil
to indoor coil
Service Valve(Valve Open)
Schradervalve
serviceport
service portcap
insert hexwrench here
to indoor coil
to outdoor coil
stem cap
FIGURE 6
Vapor Line Ball Valve – 5 Ton Units Only
Vapor line service valves function the same way as the other
valves, the difference is in the construction. A ball valve is
illustrated in figure 7.
The ball valve is equipped with a service port with a factory−
installed Schrader valve. A service port cap protects the
Schrader valve from contamination and assures a leak−free
seal.
Page 12
Ball Valve (Valve Open)
FIGURE 7
Schrader valve
service port
service portcap
stem cap
stem
Use Adjustable WrenchTo open: rotate Stem Clockwise 90°.
To close: rotate Stem Counter-clockwise 90°.
ball(shown open)
to outdoor coil
to indoor coil
IV − CHARGING
WARNINGR−410A refrigerant can be harmful if it is inhaled.R−410A refrigerant must be used and recovered re-sponsibly.
Failure to follow this warning may result in personalinjury or death.
A − Leak Testing
After the line set has been connected to the indoor and out-
door units, check the line set connections and indoor unit
for leaks.
IMPORTANTThe Clean Air Act of 1990 bans the intentional ventingof (CFC’s and HFC’s) as of July 1, 1992. Approvedmethods of recovery, recycling or reclaiming must befollowed. Fines and/or incarceration my be levied fornoncompliance.
WARNINGFire, Explosion and Personal SafetyHazard.Failure to follow this warning couldresult in damage, personal injury ordeath.Never use oxygen to pressurize orpurge refrigeration lines. Oxygen,when exposed to a spark or openflame, can cause damage by fireand / or an explosion, that can re-sult in personal injury or death.
WARNINGDanger of explosion!
When using a high pressure gas suchas dry nitrogen to pressurize a refriger-ant or air conditioning system, use aregulator that can control the pressuredown to 1 or 2 psig (6.9 to 13.8 kPa).
Using an Electronic Leak Detector
1 − Connect a cylinder of R−410A to the center port of the
manifold gauge set. Connect manifold gauge to service
valve port.
2 − With both manifold valves closed, open the valve on the
R−410A cylinder.
3 − Open the high pressure side of the manifold to allow the
R−410A into the line set and indoor unit. Weigh in a trace
amount of R−410A. [A trace amount is a maximum of 2
ounces (57 g) or 3 pounds (31 kPa) pressure.] Close the
valve on the R−410A cylinder and the valve on the high
pressure side of the manifold gauge set. Disconnect the
R−410A cylinder.
4 − Connect a cylinder of nitrogen with a pressure regulat-
ing valve to the center port of the manifold gauge set.
5 − Connect the manifold gauge set high pressure hose to
the vapor valve service port. (Normally, the high pres-
sure hose is connected to the liquid line port; however,
connecting it to the vapor port better protects the man-
ifold gauge set from high pressure damage.)
6 − Adjust the nitrogen pressure to 150 psig (1034 kPa).
Open the valve on the high side of the manifold gauge
set which will pressurize line set and indoor unit.
7 − After a few minutes, open a refrigerant port to ensure
the refrigerant you added is adequate to be detected.
(Amounts of refrigerant will vary with line lengths.)
Check all joints for leaks. Purge nitrogen and R−410A
mixture. Correct any leaks and recheck.
B − Evacuating
Evacuating the system of noncondensables is critical for
proper operation of the unit. Noncondensables are defined
as any gas that will not condense under temperatures and
pressures present during operation of an air conditioning
system. Noncondensables and water vapor combine with
refrigerant to produce substances that corrode copper pip-
ing and compressor parts.
NOTE − This evacuation process is adequate for a new
installation with clean and dry lines. If excessive mois-
ture is present, the evacuation process may be required
more than once.
IMPORTANTUse a thermocouple or thermistor electronic vacuumgauge that is calibrated in microns. Use an instrumentthat reads from 50 microns to at least 10,000 microns.
Page 13
1 − Connect manifold gauge set to the service valve ports :
� low pressure gauge to vapor line service valve � high pressure gauge to liquid line service valve
2 − Connect micron gauge.
3 − Connect the vacuum pump (with vacuum gauge) to the
center port of the manifold gauge set.
4 − Open both manifold valves and start the vacuum
pump.
5 − Evacuate the line set and indoor unit to an absolute
pressure of 23,000 microns (29.01 inches of mercury).
During the early stages of evacuation, it is desirable to
close the manifold gauge valve at least once to deter-
mine if there is a rapid rise in absolute pressure. A rap-
id rise in pressure indicates a relatively large leak. If this
occurs, repeat the leak testing procedure.
NOTE − The term absolute pressure means the total
actual pressure within a given volume or system, above
the absolute zero of pressure. Absolute pressure in a
vacuum is equal to atmospheric pressure minus vacu-
um pressure.
6 − When the absolute pressure reaches 23,000 microns
(29.01 inches of mercury), close the manifold gauge
valves, turn off the vacuum pump and disconnect the
manifold gauge center port hose from vacuum pump.
Attach the manifold center port hose to a nitrogen cylin-
der with pressure regulator set to 150 psig (1034 kPa)
and purge the air from the hose with nitrogen. Open the
manifold gauge valves to break the vacuum in the line
set and indoor unit. Close the manifold gauge valves.
CAUTIONDanger of Equipment Damage.Avoid deep vacuum operation. Do not use compres-sors to evacuate a system.Extremely low vacuums can cause internal arcing andcompressor failure.Damage caused by deep vacuum operation will voidwarranty.
7 − Shut off the nitrogen cylinder and remove the manifold
gauge hose from the cylinder. Open the manifold gauge
valves to release the nitrogen from the line set and in-
door unit.
8 − Reconnect the manifold gauge to the vacuum pump,
turn the pump on, and continue to evacuate the line set
and indoor unit until the absolute pressure does not rise
above 500 microns (29.9 inches of mercury) within a
20−minute period after shutting off the vacuum pump
and closing the manifold gauge valves.
9 − When the absolute pressure requirement above has
been met, disconnect the manifold hose from the vacu-
um pump and connect it to an upright cylinder of R−410A
refrigerant. Open the manifold gauge valves to break the
vacuum from 1 to 2 psig positive pressure in the line set
and indoor unit. Close manifold gauge valves and shut
off the R−410A cylinder and remove the manifold gauge
set.
C − Charging
NOTES −
� R−410A refrigerant cylinders are rose−colored. Re-frigerant should be added through the vapor valvein the liquid state.
� Certain R−410A cylinders are identified as beingequipped with a dip tube. These allow liquid refrig-erant to be drawn from the bottom of the cylinderwithout inverting the cylinder. DO NOT turn this typecylinder upside−down to draw refrigerant.
IMPORTANTUse table 6 to perform maintenance checks. Table 6 isnot a procedure for charging the system. Minor varia-tions in these pressures may be due to differences ininstallations. Significant deviations could mean thatthe system is not properly charged or that a problemexists with some component in the system.
This system is charged with R−410A refrigerant which oper-
ates at much higher pressures than R−22. The installed liq-
uid line filter drier is approved for use with R−410A. Do not
replace it with components designed for use with R−22. This
unit is NOT approved for use with coils which use capillary
tubes as a refrigerant metering device.
Factory Charge
Units are factory charged with the amount of R−410A refrig-
erant indicated on the unit rating plate. This charge is based
on a matching indoor coil and outdoor coil with 15 ft. (4.6 m)
line set. For varying lengths of line set, refer to table 2 for re-
frigerant charge adjustment.
TABLE 2
Refrigerant Charge per Line Set Lengths
Liquid LineSet Diameter
Oz. per 5 ft. (g per 1.5 m) adjustfrom 15 ft. (4.6 m) line set*
3/8 in. (9.5 mm) 3 ounce per 5 ft. (85 g per 1.5 m)
*If line length is greater than 15 ft. (4.6 m), add this amount.
If line length is less than 15 ft. (4.6 m), subtract this
amount.
Page 14
IMPORTANTMineral oils are not compatible with R−410A. If oilmust be added, it must be a polyol ester oil.
The compressor is charged with sufficient polyol es-ter oil for approved line set lengths.
Units Delivered Void of ChargeIf the system is void of refrigerant, clean the system usingthe procedure described below.
1 − Use dry nitrogen to pressurize the system and check for
leaks. Repair leaks, if possible.
2 − Evacuate the system to remove as much of the moisture
as possible. Use dry nitrogen to pressurize the system
and check for leaks. Repair leaks, if possible.
3 − Use dry nitrogen to break the vacuum and install the pro-
vided filter drier in the system.
4 − Evacuate the system again. Then, weigh the appropriate
amount of R−410A refrigerant (listed on unit nameplate)
into the system.
5 − Monitor the system to determine the amount of moisture
remaining in the oil. Use test kit 10N46 to verify that the
moisture content is within the kit’s dry color range. It
may be necessary to replace the filter drier several
times to achieve the required dryness level.
If system dryness is not verified, the compressor
will fail in the future.
Checking ChargeThe outdoor unit should be charged during warm weather.However, applications arise in which charging must occur inthe colder months. The method of charging is determined bythe unit’s refrigerant metering device and the outdoorambient temperature.
Measure the liquid line temperature and the outdoor ambi-ent temperature as outlined below:
1 − Connect the manifold gauge set to the service valves:
� low pressure gauge to vapor valve service port� high pressure gauge to liquid valve service port
2 − Close manifold gauge set valves. Connect the center
manifold hose to an upright cylinder of R−410A .
3 − Set the room thermostat to call for heat. This will create
the necessary load for properly charging the system in
the cooling cycle.
4 − Record outdoor ambient temperature using a digital ther-
mometer.
5 − When the heating demand has been satisfied, switch the
thermostat to cooling mode with a set point of 68�F
(20�C). When pressures have stabilized, use a digital
thermometer to record the liquid line temperature.
6 − The outdoor temperature will determine which charging
method to use. Proceed with the appropriate charging
procedure.
Charge Using Weigh-in Method TXV Systems�
Outdoor Temp. < 65ºF (18ºC)
If the system is void of refrigerant, or if the outdoor ambienttemperature is cool, first, locate and repair any leaks andthen weigh in the refrigerant charge into the unit.
1 − Recover the refrigerant from the unit.
2 − Conduct leak check; evacuate as previously outlined.
3 − Weigh in the unit nameplate charge. If weighing facilities
are not available or if charging the unit during warm
weather, use one of the following procedures.
Charge Using the Subcooling Method – Outdoor Temperature < 65°F (18°C)
When the outdoor ambient temperature is below 65°F(18°C), use the subcooling method to charge the unit. Val-ues from (table 3) are used for this procedure.
If necessary, restrict air flow through the outdoor coil toachieve pressures in the 325−375 psig (2240−2585 kPa)range. Higher pressures are necessary for checking thecharge. Block equal sections of air intake panels and moveobstructions sideways until the liquid pressure is in the325−375 psig (2240−2585 kPa) range. See figure 11.
Blocking Outdoor Coil
*Outdoor coil should be blocked oneside at a time with cardboard or plasticsheet until proper testing pressures arereached.
cardboard or plastic sheet
*Four−sided unit shown.
FIGURE 11
1 − With the manifold gauge hose still on the liquid service
port and the unit operating stably, use a digital thermom-
eter to record the liquid line temperature.
2 − At the same time, record the liquid line pressure reading.
3 − Use a temperature/pressure chart (table 3) to determine
the saturation temperature for the liquid line pressure
reading.
4 − Subtract the liquid line temperature from the saturation
temperature (according to the chart) to determine sub-
cooling.
Page 15
5 − Compare the subcooling value with those in table 4. If
subcooling is greater than shown, recover some refrig-
erant. If subcooling is less than shown, add some refrig-
erant. Be aware of the R−410A refrigerant cylinder. It will
be light maroon−colored. Refrigerant should be added
through the vapor line valve in the liquid state.
TABLE 3
R−410A Temperature (°F) − Pressure (Psig)
°F Psig °F Psig °F Psig °F Psig
32 100.8 64 181.6 96 299.4 126 451.8
34 105.0 66 187.7 98 308.2 128 463.5
36 109.2 68 194.1 100 317.2 130 475.6
38 113.6 70 200.6 102 326.4 132 487.8
40 118.0 72 207.2 104 335.7 134 500.2
42 122.6 74 214.0 106 345.3 136 512.9
44 127.3 76 220.9 108 355.0 138 525.8
46 132.2 78 228.0 110 365.0 140 539.0
48 137.1 80 235.3 112 375.1 142 552.3
50 142.2 82 242.7 114 385.4 144 565.9
52 147.4 84 250.3 116 396.0 146 579.8
54 152.8 86 258.0 118 406.7 148 593.8
56 158.2 88 266.0 120 417.7 150 608.1
58 163.9 90 274.1 122 428.8 152 622.7
60 169.6 92 282.3 124 440.2 154 637.5
62 195.5 94 290.8 126 451.8 156 652.4
TABLE 4
XC16 Subcooling Values for Charging
� Saturation Temperature
� � Liquid Line Temperature
= � Subcooling Value
Model −024 −036 −048 −060
°F (°C)* 5 (2.8) 6 (3.3) 6 (3.3) 9 (5)
*F: +/−1.0°; C: +/−0.5°
Charge Using the Approach Method,TXV Systems�Outdoor Temperature > 65ºF (18ºC)
The following procedure is intended as a general guide and is
for use on expansion valve systems only. For best results, in-
door temperature should be 70°F (21°C) to 80°F (26°C).
Monitor system pressures while charging.
1 − Record outdoor ambient temperature using a digital
thermometer.
2 − Attach high pressure gauge set and operate unit for sev-
eral minutes to allow system pressures to stabilize.
3 − Compare stabilized pressures with those provided intable 6, �Normal Operating Pressures." Pressures high-er than those listed indicate that the system is over-charged. Pressures lower than those listed indicate thatthe system is undercharged. A temperature/pressurechart for R−410A refrigerant is provided in table 3 foryour convenience. Verify adjusted charge using the ap-proach method.
NOTE − Use the same digital thermometer you used tocheck the outdoor ambient temperature to check the liq-uid line temperature.
4 − The difference between the ambient and liquid tempera-tures should match values given in table 5. If the valuesdon’t agree with the those in table 5, add refrigerant tolower the approach temperature, or recover refrigerantfrom the system to increase the approach temperature.Be aware of the R−410A refrigerant cylinder. It will belight maroon−colored. Refrigerant should be addedthrough the vapor valve in the liquid state.
TABLE 5
XC16 Approach Values for Charging
� Liquid Line Temperature
� � Outdoor Temperature
= � Approach Temperature
Model −024 −036 −048 −060
°F (°C)* 8 (4.4) 10 (5.6) 8 (4.4) 4 (2.2)
*F: +/−1.0°; C: +/−0.5°
IMPORTANTTable 6 is not a procedure for charging the system butmay be used to perform maintenance checks. Minorvariations in these pressures may be due to differ-ences in installations. Significant deviations couldmean that the system is not properly charged or thata problem exists with some component in the system.
TABLE 6
Normal Operating Pressures In psig (liquid +/− 10 and vapor+/− 5 PSIG)*
*These are typical pressures only. Indoor indoor match up, in-
door air quality, and indoor load will cause the pressures to vary.
Page 16
V − SERVICE AND RECOVERY
WARNINGPolyol ester (POE) oils used with R−410A refrigerantabsorb moisture very quickly. It is very importantthat the refrigerant system be kept closed as muchas possible. DO NOT remove line set caps or servicevalve stub caps until you are ready to make connec-tions.
IMPORTANTUSE RECOVERY MACHINE RATED FOR R−410AREFRIGERANT.
If the XC16 system must be opened for any kind of service,
such as compressor or drier replacement, you must take ex-
tra precautions to prevent moisture from entering the sys-
tem. The following steps will help to minimize the amount of
moisture that enters the system during recovery of R−410A.
1 − Use a regulator−equipped nitrogen cylinder to break the
system vacuum. Do not exceed 5 psi. The dry nitrogen
will fill the system, purging any moisture.
2 − Remove the faulty component and quickly seal the sys-
tem (using tape or some other means) to prevent addi-
tional moisture from entering the system.
3 − Do not remove the tape until you are ready to install new
component. Quickly install the replacement compo-
nent.
4 − Evacuate the system to remove any moisture and other
non−condensables.
Any time the XC16 sealed system is opened, the drier
must be replaced and the system must be evacuated.
Any moisture not absorbed by the polyol ester oil can be re-
moved by evacuation. Moisture that has been absorbed by
the compressor oil can be removed by replacing the drier.
IMPORTANTEvacuation of system only will not remove moisturefrom oil. Drier must be replaced to eliminate mois-ture from POE oil.
VI − MAINTENANCE
WARNINGElectric shock hazard. Can cause inju-ry or death. Before attempting to per-form any service or maintenance, turnthe electrical power to unit OFF at dis-connect switch(es). Unit may havemultiple power supplies.
At the beginning of each cooling season, the system shouldbe serviced. In addition, the system should be cleaned asfollows:
A − Outdoor Unit
1 − Clean and inspect the outdoor coil. The coil may be
flushed with a water hose. Ensure the power is turned
off before you clean the coil.
2 − Condenser fan motor is prelubricated and sealed. No
further lubrication is needed.
3 − Visually inspect connecting lines and coils for evidence
of oil leaks.
4 − Check wiring for loose connections.
5 − Check for correct voltage at unit (unit operating).
6 − Check amp−draw condenser fan motor.
Unit nameplate _________ Actual ____________ .
NOTE − If owner complains of insufficient cooling, the unit
should be gauged and refrigerant charge checked. Refer to
section on refrigerant charging in this instruction.
B − Indoor Coil
1 − Clean coil, if necessary.
2 − Check connecting lines and coils for evidence of oil
leaks.
3 − Check the condensate line and clean it if necessary.
C − Indoor Unit
1 − Clean or change filters.
2 − Adjust blower speed for cooling. Measure the pressure
drop over the coil to determine the correct blower CFM.
Refer to the unit information service manual for pressure
drop tables and procedure.
3 − Belt Drive Blowers − Check belt for wear and proper ten-
sion.
4 − Check all wiring for loose connections
5 − Check for correct voltage at unit (blower operating).
